Neutron generators are required for a wide variety of national and homeland security field-based activities related to nuclear terrorism and nonproliferation. Despite a 2002 National Academy study in which the need for improved compact neutron generators was noted, a compact generator with the required characteristics of neutron output, longevity, robust character, and reasonable cost does not yet exist.
Compact neutron generators are typically of the deuterium-deuterium (DD) or deuterium-tritium (DT) type, and fall broadly into two categories depending on the hydrogen isotope ion source used. The first type uses low-pressure gas discharge-based ion sources, such as a Penning discharge. The second type uses a spark or arc discharge that provide relatively high-output generators with limited lifetimes. The high output is due to the ionization of, for example, deuterium stored at high density in metal deuterides and the significant ion current that can be extracted from what can be ampere-level, high-current density discharges. A factor limiting the lifetime of these sources is erosion of the metal hydride by the electrical spark or arc.
Relevant art: U.S. Pat. Nos. 4,092,381; 4,224,261; 4,252,610.